HYPERCAPNBIC NORMALIZATION OF BOLD FMRI: COMPARISON ACROSS FIELD STRENGTHS & PU

BOLD FMRI 的高碳酸正常化：跨场强的比较

• 批准号: 7601623
• 负责人: SEONG KIM
• 金额: $ 4.72万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-06-01 至 2008-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7601623
• 关键词: Behavior; Blood; Blood Volume; Blood capillaries; Breathing; Cerebrovascular Circulation; Cerebrum; Computer Retrieval of Information on Scientific Projects Database; Condition; Data; Effectiveness; Fingers; Functional Magnetic Resonance Imaging; Funding; Gases; Grant; Hypercapnia; Institution; Localized; Methods; Motor; Movement; Physiologic pulse; Physiological; Pulse taking; Research; Research Personnel; Resources; Rest; Signal Transduction; Source; Specificity; Stimulus; Tissues; United States National Institutes of Health; Veins; Venous; base; blood flow measurement; blood oxygen level dependent; capillary; human subject; improved; magnetic field; neural stimulation; relating to nervous system; response; size

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) signal response to neural stimulation is influenced by many factors that are unrelated to the stimulus. These factors are physiological, such as the resting venous cerebral blood volume (CBV(v)) and vessel size, as well as experimental, such as pulse sequence and static magnetic field strength (B(0)). Thus, it is difficult to compare task-induced fMRI signals across subjects, field strengths, and pulse sequences. This problem can be overcome by normalizing the neural activity-induced BOLD fMRI response by a global hypercapnia-induced BOLD signal. To demonstrate the effectiveness of the BOLD normalization approach, gradient-echo BOLD fMRI at 1.5, 4, and 7 T and spin-echo BOLD fMRI at 4 T were performed in human subjects. For neural stimulation, subjects performed sequential finger movements at 2 Hz, while for global stimulation, subjects breathed a 5% CO(2) gas mixture. Under all conditions, voxels containing primarily large veins and those containing primarily active tissue (i.e., capillaries and small veins) showed distinguishable behavior after hypercapnic normalization. This allowed functional activity to be more accurately localized and quantified based on changes in venous blood oxygenation alone. The normalized BOLD signal induced by the motor task was consistent across different magnetic fields and pulse sequences, and corresponded well with cerebral blood flow measurements. Our data suggest that the hypercapnic normalization approach can improve the spatial specificity and interpretation of BOLD signals, allowing comparison of BOLD signals across subjects, field strengths, and pulse sequences. A theoretical framework for this method is provided.

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 血液氧合水平依赖(BOLD)功能磁共振成像(FMRI)对神经刺激的信号响应受许多与刺激无关的因素影响。这些因素既是生理的，如静息静脉脑血容量(CBV(V))和血管大小，也是实验的，如脉冲序列和静磁场强度(B(0))。因此，很难比较不同受试者、不同场强和不同脉冲序列的任务诱发功能磁共振信号。这个问题可以通过用全球高碳酸血症诱导的BOLD信号使神经活动诱导的BOLD fMRI反应正常化来克服。为了证明BOLD归一化方法的有效性，对受试者进行了1.5、4和7T的梯度回波BOLD功能磁共振成像和4T的自旋回波BOLD功能磁共振成像。对于神经刺激，受试者以2赫兹的频率进行连续的手指运动，而对于整体刺激，受试者呼吸5%的CO(2)混合气体。在所有条件下，主要包含大静脉的体素和包含主要活动组织的体素(即毛细血管和小静脉)在高碳酸化正常化后表现出明显的行为。这使得仅根据静脉血氧的变化就可以更准确地定位和量化功能活动。运动任务产生的归一化BOLD信号在不同的磁场和脉冲序列中是一致的，并与脑血流量测量结果相一致。我们的数据表明，高二氧化碳归一化方法可以改善BOLD信号的空间特异性和解释，允许比较不同受试者、场强和脉冲序列的BOLD信号。为该方法提供了一个理论框架。